The present invention relates generally to articles of furniture and, more particularly, to a deflectable seat back mechanism for supporting a seat back relative to a seat member and for allowing a limited amount of deflection of the seat back relative to the seat.
It is known in the furniture industry to construct the interconnection of the seat base and seat back of a chair to allow a small amount of deflection of the seat back relative to the seat base, i.e., an increase in the included angle between the seat base and the seat back. For example, commonly assigned U.S. Pat. No. 3,973,798 discloses a pair of spaced, spring rods adapted to support the seat back relative to the seat base and to permit, upon application of pressure to the seat back, a relative amount of deflection therebetween. Other arrangements for deflectable chair backs include supporting the seat back from a single, centrally located flat spring member. This arrangement is common in office/secretarial chairs and the like. The flat spring member allows deflection of the seat back relative to the seat base upon the application of pressure to the seat back.
One disadvantage of the known arrangements for achieving a deflectable seat back is that they do not provided sufficient lateral and torsional support for the seat back. That is, if pressure is unequally applied to the seat back, the seat back is caused to twist as well as deflect or to deflect laterally relative to the seat base generally making the chair less comfortable. In addition, these known arrangements do not provide for allowing the user to adjust the amount of force required to cause deflection of the seat back. Moreover, these known deflectable seat back designs do not provide for detaching the chair back such that the chair can be made compact for shipping and storage.